This invention relates to Hall-effect sensor devices which can suitably be utilized, for example, for detecting crankshaft angle of an internal combustion engine for controlling the ignition timing.
Various sensor devices, such as position sensors, angle detectors, and velocity sensors, utilizing the Hall effect for converting variations of magnetic flux into an electrical signal are well known. Further, Hall IC's (ingegrated circuits) which incorporate a Hall element in a hybrid integrated circuit mounted on a substrate which is made, for example, of a ceramic material, are also well known. Furthermore, Hall-effect sensor devices including such a Hall IC which is integrated with a magnetic circuit, for the purpose of controlling the ignition timing of an internal combustion engine are also known.
However, the conventional Hall-effect sensor devices have the following disadvantages. Namely, during the molding process of the casing or frame thereof, the constitutive parts of the Hall-effect sensor device, such as the Hall IC or the magnetic circuit parts, must be precisely positioned and fixed within a mold, utilizing a number of jigs for the respective parts. Then, a thermosetting resin is poured into the mold while the parts are thus kept in their respective positions, and then dried and set in a heating furnace. Thus, the process is in need of a multitude of jiqs for fixing the parts at their respective relative positions during the molding, and hence the accuracy of the positioning of the parts is low. As a result this process is not suitable for automated mass production. In addition, the Hall sensor devices produced by this process are low in their signal accuracy.